(Photo: REUTERS / Anindito Mukherjee)A worker of Bharatiya Janata Party (BJP) rides his bicycle past the party's campaign billboard featuring Prime Minister Narendra Modi outside their party headquarters in New Delhi February 10, 2015. Upstart anti-establishment Aam Aadmi Party crushed the ruling Bharatiya Janata Party in an election for the Delhi assembly on Tuesday, smashing an aura of invincibility built around Prime Minister Narendra Modi since he swept to power last year. The billboard reads: "One India, Best India"

Christianity and Islam are under attack by extremists in India, the world's second most populous nation, say the groups religious monitors and human rights grups.

The latest accusations come from International Christian Concern quoting the Catholic Secular Forum in India and show that persecution in the name of religion is not exclsuive to any set of beliefs .

Violent attacks on religious minorities in India averaged one attack a day last year, a rising number that has led a coalition of U.S. Congress members to plead with India's leaders to condemn the violence, International Christian Concern reported March 17.

A total of 34 members of the US Congress, including eight senators and 26 representatives from both parties sent a letter to Modi in February.

It it they expressed their "grave concerns about the increasing intolerance and violence members of India's religious minority communities experience."

"We urge your government to take immediate steps to ensure that the fundamental rights of religious minorities are protected and that the perpetrators of violence are held to account," they wrote.

ICC cited the Catholic Secular Forum that attacks rose more than 20 percent from 2014 to 2015.

There have been 36 attacks on Christians so far this year, ranging from churches being destroyed to priests, nuns, and parishioners being beaten, ICC said as well as four brutal killings of Muslim men by Hindu mobs after they were accused of consuming beef.

For Hindus cattle are sacred.

The Indian government failed to address increasing attacks on free expression and against religious minorities, Human Rights Watch said in its World Report 2016.

Indian authorities blocked foreign funding and increased restrictions on civil society groups critical of the government or large development projects, HRW said.

GROWING HINDU NATIONALISM

Christian groups monitoring the upsurge in violence say it has coincided with escalting Hindu nationalism, encompassing a wide spectrum of Indian political movements, which believe that Hindu traditions and beliefs should serve as a guide for India and its citizens.

The country's Prime Minister, Narendra Modi, who heads the Bharatiya Janata Party has ingored the extremists and even condoned, extremist attacks.

The BJP, or India People's Party, has close ideological and organizational links to the Hindu nationalist Rashtriya Swayamsevak Sangh that presents itself as a nationalist cultural group under a Hindu banner.

"It's a radical Hindu ideology," said William Stark, an expert in South Asia with ICC. "If you see someone Muslim or Christian, they're following a foreign faith, and they're defiling India because they're following a foreign faith."

The past year was the worst one for Indian Christians in the history of post-Independence India, a report released by the forum stated, the Hindustani Times reported earlier in the year.

"There were 120 attacks in 2014. The attacks have more than tripled in the last one year," CSF general secretary Joseph Dias told the Hindustani Times.

The CSF report said: "There has been a very marked rise in attacks on minorities with the swearing in of BJP-led governments at the center as well as the states," with the blame going to Hinduvta groups.

Such groups push aggressive Hindu nationalism in the country where Hindus make up almost 80 percent of the 1.25 million people, Muslims 14 percent and Christians 2.3 percent.

CSF said the majority of attacks on minority groups go unreported because "the victims are too scared to complain," and only those brought to the attention of the police were documented.

"There were some shocking cases of persecution that we were forced to leave out because the police and politicians forced the victims to compromise with their attackers," Dias said.